Osteoporosis is a major public health threat. The American Association of Orthopaedic Surgeons estimates that the cost of treating patients with a low-energy fracture in 2004 was US$24.2 billion, and projected costs for care of osteoporosis and low-energy fractures over the next two decades are $474 billion. Current treatments for osteoporosis include several anti-resorptive (or anti-catabolic) and some anabolic agents. VDRMs such as calcitriol are currently used to treat osteoporosis in several ex-US countries. VDRMs influence bone metabolism through regulation of intestinal calcium absorption, parathyroid hormone, receptor activator of nuclear factor-kB ligand, and also via direct effects on osteoblasts and osteoclasts. Despite encouraging data on VDRM's benefits for treating osteoporosis, VDRMs are not used in osteoporosis patients in the US likely due to the fact that those currently on the market have substantial hypercalcemic toxicity that interferes with calcium homeostasis. Consequently VDRM therapy requires frequent serum calcium monitoring and dose titration. An ideal VDRM should be with little or no hypercalcemic toxicity in the efficacious dose range. Since VDRMs are well known to have anabolic effects on the bone, a VDRM without hypercalcemic toxicity for the treatment of osteoporosis will provide significant benefits to patients receiving the standard of care. Vidasym has taken a unique approach to discover and develop novel VDRMs such as VS-105. Data from extensive animal studies show that VS-105 has an exceptionally wide therapeutic index (TI) at >50-fold (vs. TI of calcitriol at 1 fold). Results from SBIR Phase I confirm that VS-105 exhibits potent anabolic effects on the bone in a dose range that does not affect serum calcium. The mechanism of action studies demonstrate that, while VS-105 is potent in stimulating osteoblast activities, osteoclast activitie are reduced, leading to an increase in bone growth, bone mineral density, and bone volume. These positive data strongly support the advancement of VS-105 into Phase II SBIR. The specific aims of this Phase II study are: (1) To complete synthesis and formulation of VS-105 under Good Manufacturing Practice (GMP) in preparation for a Phase I clinical study. (2) To file an IND with the FDA for the indication of osteoporosis in preparation for a Phase I clinical study with VS-105. Vidasym plans to develop VS-105 into a reimbursable prescription drug to treat osteoporosis in patients receiving the standard of care. According to a 2012 report from GBI Research, the osteoporosis therapeutics market in 2010 was at $10.2 billion, and is forecasted to grow at a CAGR of 10.3% to $22.4 billion in 2018. An independent report by EvaluatePharma stated that osteoporosis medications achieved US$13 billion in annual worldwide sales in 2012, and this number is likely to increase based on the projections of increased patient numbers. Assuming Vidasym's VS-105 has a modest 5% penetration into the osteoporosis market when launched in 2018, the estimated annual sales will be US$1+ billion.